Device and a process for controlling the crimping arc in compression crimping of strands of fibers



J. 28, 1958 I H. WEGENER 2,820,988

AND A PROCESS FOR DEVICE CONTROLLING THE CRIMPING ARC IN COMPRESSIONCRIMPING OF STRANDS 0F FIBERS Filed May 27, 1954' PNEUMATIC RELAYCURRENT SUPPLY sounce- IHHHHH INVEN TOR.

%MMLWWW/ United States Patent F DEVICE AND A PROCESS FOR CONTROLLING THECRIMPING ARC IN COMPRESSION CRIMP- lNG OF STRANDS 0F FIBERS HarryWegener, Ems, Switzerland, assignor to Inventa A. G. fuer Forschung undPatentverwertung, Zurich, Switzerland Application May 27, 1954, SerialNo. 432,812

Claims priority, application Switzerland May 28, 1953 5 Claims. (CI.19-66) The present invention relates to a process for controlling thecrimping arc in compression crimping of a strand of fibers, and a devicetherefor.

Compression crimping has recently been used on a large scale for theproduction of imitation wool from staple fiber. In the known processes,the compression crimping of fiber strands or cables for spinning,however, does not result in a definite crimping for each fibril presentin the strand determined by the are number per cm., but the are numbersvary within a certain range.

The variation of the crimping number over the above mentioned range is,with given adjustment, generally a function of the crimping pressure.The crimping pressure is not a constant during the operation, since itdepends on various factors, such as fluctuations of the titre, changesin the moisture content of the strand, etc.; the crimping number has,therefore, to be regularly tested. The crimping pressure is thenregulated manually according to the test results. The high rates, atwhich strands are moved in modern processing, require very short testintervals in order to avoid considerable lengths of fibers to beproduced which do not come up to crimping specifications.

The present invention relates to a process and device for compressioncrimping and more specifically for the automatic control of the crimpingarc in fiber strands for spinning. In this process, the ratio of thespeed of the strand moving out of the crimping device and the speed atwhich the strand is drawn oflE by the machine following the crimper isso adjusted, that a certain amount of the fiber will collect on a scalewhere it is constantly weighed, the deviations from a certain adjustedvalue being used for the regulation of the crimping pressure in thecrimping chamber.

The process is based on the fact that a smooth strand entering into thecrimping device is shortened by the crimping process. The amount of theshortening corresponds to the degree of crimping which is expressed bythe ratio of smooth strand and the crimped strand. If the strand leavingthe crimping device is passed on to the machine drawing it off, which isusually a cutting device, the latter has to run more slowly than thecrimping device in accordance with the ratio above specified. When aconstant crimping pressure and a constant crimping degree are used, thelength of strand between the two devices is at all times the same; ifthe crimping pressure is changed, the height of the individual crimpingarcs is likewise changed, which also alters the are number and therebythe degree of crimping.

Since, however, the ratio of speeds of the two machines remains thesame, the change in the degree of crimping is shown by the fact that adifferent length of strand than heretofore will be between the twomachines. If, with a constant degree of crimping, for instance, thestrand between the two machines exhibits a certain slack, the magnitudeof the slack changes in accordance with the changing degree of crimping.The slack becomes smaller as the degree of crimping increases and2,820,988 Patented Jan. 28, 1958 the slack becomes larger, as thecrimping degree decreases.

In accordance with the present invention, the change in lengths of thestrand between the two machines may also be made recognizable in anothermanner, and it may at the same time be used for the automatic regulationof the degree of crimping and of the are number associated therewith.If, for instance, the crimped strand emerging from the crimping deviceis first allowed to drop into a container where a certain amount is.stored, the cutting machine will, with a constant degree of crimpingbeing maintained, draw 01f exactly the same lengths as delivered by thecrimping device. The stored amount in the container does not change inweight. When the container is placed on the scale, the indicator of thelatter will invariably point at the same mark. If at this time thecrimping pressure is increased, the degree of crimping will rise, i. e.the crimped strand will be comparatively shorter than before. Since,however, the speeds of both machines are not changed, the cuttingmachine moves comparatively too fast, that is to say, it pulls off alonger strand than the one delivered from the crimping device.Consequently, the content of the container decreases and the scale showsreduction in weight.

In the opposite case, when a larger strand length is delivered by thecrimping device than pulled ofi by the cutting machine, the scale willindicate an increase in weight of the stored fiber and this willcorrespond to a decrease in the degree of crimping.

According to the present invention, the admissible range in thevariation of the crimping degree is measured by the use of two limitmarks on the graduated plate of the scale; when the indicator reachesthese limit marks, a servomotor is actuated which controls the crimpingpressure in the crimping device.

In the accompanying drawing, a device according to the invention forcarrying out the process heretofore de-' scribed is illustrated by wayof example in a preferred embodiment. It should, however be understood,that the example is given by way of illustration and not by limitationand that many changes in the details may be made without departing fromthe spirit of the invention.

A smooth strand indicated at 1 is introduced into a compression chamber3 by means of two feeding rollers 2. The exit opening from the chamberis closed at first, for instance by a fiap 12 in the sidewall of thechamber which is spring-controlled by a spring 13. With flap 12 inclosed position, chamber 3 will be filled up until by further fillingthe contents are compressed. This will continue until the pressure inthe chamber reaches a degree that will allow it to overcome thecounter-pressure of spring 13, so that the chamber opens up. Anequilibrium will be formed between the crimping pressure inside and thespring pressure outside and on this equilibrium the degree of crimpingwill depend. A screw 14 is provided for the adjustment of the pressureoperating as crimping pressure. The regulation of screw 14 is controlledby a servomotor 15, coupled with the screw.

The crimped strand 4 emerges from the crimping chamber and drops into acontainer 5 where it forms a stored amount 6, which is drawn ofi by apair of rollers 7. Container 5 is disposed on the platform of a scale 8.The scale has an indicator 9 movable on a graduated plate 10, which hastwo limit marks 11.

The pivoted end of indicator 9 is connected to one pole of a weakcurrent source S, whose other pole is connected to a conventionalelectrical or pneumatic relay A. Arranged between the relay A and themotor 15, is a current source 20. The power source S is capable ofchanging the direction of rotation of the motor 15 by reversing thepolarity of the current source 20.

As soon as indicator 9 reaches one of the marks, the

3- I servomotor 1'5'is actuated in a manner known per see, by the relaymeans A1 "The servomo'tor will 'then turn screw 14 to advanced orretracted position. Since this screw 3 .8 nlly tto, be .turncdsbycslighttdegrees, motor- 15 coupled "thereto with a large transmission. i

Furthermore, known means, ofsthe measuring technique are 'Iis'edff'orsearching the osition of indicator 59. with respecttt'o marks '11 incertain interyalsgIand to 'a djnst servo motor '15 so that it ,will runonly "fora short .Itime, whichcan "b chosen as required, in. order. tomake only a small turn in the adjustment c'ftsc'rew 14. This time,during which the motoris running, will be shorter than the time intervalbetween 'tWo' Search iop'eiatibn's of .ind am r y Between the rollers 7'and'."the feed '1'ollers"2,,a-mc't'ering device 16 is arranged'forme'a'siuring the speed, with which the strand ente'r'sfthe pair-cfro'llers'7. 'The meter 16 indicates [the quotient in crimping degrees.One wa in which this can be done is'to arranged aDQC. dynamo to bedriven by the pair of feed rollers 2 and anothe'r-DQC. dynamo driven byrolle'rs 7. "The voltages generated by the two dynamos arertransmittedin opposite directio'nsfto the meter 16, which in this case is avolt-meter. Since this meter indicates the ratio ,of the two voltageswhich are in direct proportion to the R. PQM. of the roller pairs 2 and7, the scale of the volt-meter 16 can 'be calibrated to indicatedirectly the. degree of crimping. According to the indicated degree, theratio of thewtop speeds of the rollers can be adjusted as required'in'any particular case.

Example A strand composed of 28,000'Lfibers of a; titre :of 3.75 perfibril is fed in between rollers 2. The rollers are driven at 150m./min. The chamber 3 has a capacity "of 100 'cm. The pressure which isvbrought to bear on wall 12 of'chamber 3 is adjusted to 40 kg./cm

As soon as 3 meters'of the strand have been "fed into chamber 3, thepressure insidewill have -increased to a'n amount which. causes spring13 "tomove to the righthand side (in the drawing) andwill open the exitat the bottom of chamber 3. The crimped strand will then have 18crimping arcs per lcm. on the average. 7

As the s'trand4 descends frorn chamberfi, i't'i s' collected' incontainer 5 'on 'scale 8. From" there the :strand is drawnvofi by a pairof rollers 7 which arexdrivenfat .125 M. :P. M.

The instrument 16 indicates-:in-degrecs of -cfimp'ingthe rates :ofthe-speeds cf roller' 'sys'tems and 7.

A change in pressure is automatically effected by ,the weight of theaccumulationti of strand 4 when required. The mechanism foreffectingfthat change operates as above described by means of motor 15and screw 14 acting on spring 13.

What I claim is: V p 'L K proc'ess' rm the continuous contrdlof' theping "arc in compression crimping of 'fiber -strand's;wh1ch comprisescrimping s'ai'd strands inone "operatiomwithdrawing saidstrands incrimped condition; maintaining; definite ratio between the :fe'edingofthe uncrimped strand and the withdrawing thereof in crimped condition,allowing anamount of the crimped strand to collect. forweighing the"same, and using thedeviations" in weight from an adjustedvalue forregulating the crimpinggpress'ure in V said crimping'operation. p

2. A device for the continuous "control of the crimping arc incompression crimping of fiber strands which comprises 'a crimpinchamberswith intake .ifiean's fo said strands, means for exertingad'etermined crimping. sure on the strands, means 'for withdrawing :saidtr d's" aftercrimping from said-chamber, weigliing 'fi'ie'ain'sdn r-lpo's'ed between the crimping chamber and the ing means, and control"means for "maintaining "a "defi m 0 between the -feeding of :theuncrim'ped str'an said crimping chamber 'and the withdrawing thereof itc'rimpedcdndition, the amount cf "the 'cfim ce collected on the weighingmeans being operative infregulating the crimping pressure eXe'rted'onthe strand i'r'r'the said withdrawing means of 't' heQst'r'and, :s'a'idmeteringdevice indicating the degree of crimping which serves 'as a aing a platform and inclined slide ifo'r cbliectiiigfthi is; Adevice;-according to claim -21, w er n theweig'lip ing means includes agraduated plate having two marks, and an indicator -movable overs plate;'mea'nsfbeing associated with said-indicatoribe'co ing operative, whensaid indicator Apasse's'beyon'd marks; in actuating a *servdmotorforcontrol pr'e'ssnre cXer'tingQmeans associated with 'said cngmber-t Ncrcfcren escitcdt "graduated

